The Basal Lamina

Hello everyone in this lesson. We are going to be talking about the basil lamb inna. The basil lamin A is going to be a very important structure. That is kind of like the foundation for your cells. It's going to be especially important for your epithelial cells. Okay, so the basil lamb inna acts as a thin but strong extra cellular matrix under all the types of cells but is mainly found beneath epithelial cells. Epithelial cells are going to be cells like your skin. They're also very, very important for the lining of your internal organs. For example the lining of your digestive system is made of a specialized epithelial cells and they will have a very good, very important basil lamb iness structure but it can be found in all types of tissues including muscle fat and Schwann cells which are going to surround neurons. It's also found in neurons and kidney cells. In neurons. The basil lamb inna is extra support that makes sure that the synapse between two neurons is put together correctly. Also in kidney cells it makes this kind of impermeable barrier inside of the kidney cells so that waste products don't mix with the blood. Now the basil lamb inna is incredibly small. There's a typo here, it says 40 to 120 millimeters thick. Oh my goodness, it's not that large. It's 40 to 120 nanometers thick. This is only something that you can see under a microscope. And speaking of that, we have this particular picture here of a cell and we're going to have the plasma membrane right here of this cell. So the plasma membrane and this structure right here. This other line that you see under the plasma membrane line, that dark line there that is going to be the basil lamb inna. And it's going to be composed of very important proteins and molecules in the extra cellular matrix. And it's going to be used for structural support and a foundation. Okay, everyone. Alright, so now let's go down and let's talk about it a little bit more because the basil lamin A is going to have very specific proteins that create it. So the basil laminate is composed of two two main proteins and the basil lamb mina is going to be one of the main layers or main components of the basement membrane. But sometimes it's miss said it's not correct. The basil lamanna is not the basement membrane, it's a part of the basement membrane. It's not the basement membrane in its entirety. It's just a component and it is going to be the component of the basement membrane that is composed of these two proteins and that's going to be the lamb in in proteins and the type four collagen proteins. So the lamination proteins are organizer proteins. And they're going to be glycoprotein that actually adhere to the plasma membrane of the cell. They're going to have other protea that helps them adhere to the plasma membrane of the cell. But basically that's where they are going to be and they are going to be some of the main proteins making up the basil lamb inna. You guys can see that it's named lamin A and it's very similar to lamb in in because the lamb in in proteins are going to be very important for the basil lamb inna. And remember this is going to be a glycoprotein. Okay, all right now the lamin proteins very closely associate with and bind to the type for collagen proteins and these are going to be utilized for strength for the basil lamb inna. We want this basil lamin a to be part of the foundation that the cell can adhere to and stick itself to. So we wanted to be strong collagen which is actually the most common protein in your entire their body is used for that strength. There are many different types of collagen. There are many different numbers of collagen. We're specifically talking about collagen number four, that is where this particular collagen is going to be utilized inside of the basement or the basil lamb inna. But just you guys know if you were curious of all of the proteins in your body collagen makes up from 25 to 35% of all of the proteins in your entire body, which is kind of crazy. So the type four collagen is going to be the strength, that foundation components and the lamb in ins are going to be the binding component that bind it to the plasma membrane. So, as it says here, Type four collagen links with the lamb in in and other proteins to form a rope like helix rope like matrix. Now this figure here is going to be an illustration of what a lamb in in protein would look like and they do have this particular structure which kind of looks like a trident. But I wanted to draw for you guys a little example of what it would look like on these cells. Okay, so let me draw some cells epithelial cells to be specific. We will have these three cells Now whenever you guys learned about epithelial cells, what did you learn about Epithelial cells are pretty unique because they are polarized cells. So let me write this epithelial cells and they are polarized. And what does that mean? That means that they have two unique sides on one side of the epithelial cells. It's going to be the ethical side. On the other side of the epithelial cells. It's going to be the basil side and these two different sides are separated by the tight junctions that form between the cells and they're going to have unique sets of proteins. So the typical side has its own unique set of proteins. The basil side has its own unique set of proteins. And in my drawing we're going to have the typical side here? We're gonna have the basil side down here. Now, which side do you think the basil lamin is going to be on? It's going to be on the basil side. So that's how you guys can tell which side of the epithelial cells. The basil laminate actually is on, it's on the basil side of the epithelial cells and it deals with these very interesting lamin in proteins that bind to collagen. That's where its name is going to come from. So let me start off, I'm going to draw these little proteins. These proteins are going to be the ones that actually connect the lamb inn ins to the plasma membrane. And you guys will probably learn more about these particular proteins later. They're very important. They're called integral proteins. But you'll probably learn about those later. They're very important. They adhere a lot of things to the plan the membrane of the cell. So we have these integral proteins and then from these integral proteins, we are going to have our trident shape sticking off here and these are going to be our lamb in in proteins. Okay, so this is our lamb in in protein right here and it's going to have this train it shape that sticks off of the basil membrane. Now we're going to have our collagen fibers are collagen, four fibers are going to bind. So they're going to look like this. They're basically just going to bind to the um to the lamin proteins And it's going to create this unique matrix of these collagen fibers And these collagen fibers are gonna wind together like a rope or kind of like a trellis system. And they're going to provide support. So these are collagen for proteins. Okay, hopefully you guys can see that. Let me scroll down a little bit so you can still see it. Okay, so that's what it's basically going to be to look like. If you guys want to understand more specific proteins, I would definitely recommend looking this up is really neat but this is going to be the basic structure of the basil lamb. Inna Now remember that this is going to be only one of the layers of the entire basement membrane. The extra cellular matrix gets more complex than this but just know that the basil lamin A is going to be very important for all cells but you're mostly going to find it in the epithelial cells that line your skin and line your internal organs. And guys, the basil lamin A is going to be made up of these lamination proteins that bind these collagen for fibers to the actual epithelial cells and it's going to provide them a foundation and structure. Ok guys, let's go into some practice problems

The basal lamina supports mainly which cell type?

• A. Epithelial cells
• B. Endothelial cells
• C. Connective tissue

Type IV collagen is an important protein in the basal lamina because it provides what?

• A. Organization to the proteins in the basal lamina
• B. Connections between multiple proteins in the basal lamina
• C. Tensile strength to the basal lamina